Technique Of Brachial Plexus Block Research Articles

A New Axillary Approach for Continuous Brachial Plexus Block. A Clinical and Anatomic Study

Catheter insertion in the neurovascular space by axillary approach allows a continuous brachial plexus block and/or postoperative analgesia. We developed a perivenous technique whereby the approach to the neurovascular sheath is guided under fluoroscopy by a preopacified axillary vein. A randomized study compared this technique to the technique of Selander in ASA grade I-II patients scheduled for surgery or painful physiotherapy of the hand. The study was performed in 36 patients randomly divided into two groups. In Group 1 (n = 18), the catheter was placed according to the technique described by Selander. In Group 2 (n = 18), the catheter was placed using our perivenous technique. A complete block was obtained in all the patients of Group 2 vs only 50% of the patients in Group 1 (P < 0.05). In Group 1 a partial block was observed in 17%, with failure in 33% of the patients. There was no difference in the two groups regarding the time required to perform either technique, the duration of the complete block, the pain score, or the amount of continuously administrated bupivacaine during the first 48 h postoperatively. The plasma concentrations of total bupivacaine (high-performance liquid chromatography) were low in successful blocks, with no differences in the two groups; the median value was 0.68 microgram/mL (95% confidence interval: 0.62-0.89). The concentrations were higher (P < 0.01) in failed blocks; the median value was 1.69 micrograms/mL (95% confidence interval: 0.58-2.8). A complementary anatomic study of three arms from fresh cadavers allowed verification of the correct localization of the Teflon cannula and flexible catheter, as well as homogeneous diffusion of the methylene blue inside the brachial plexus. The perivenous technique for continuous axillary brachial plexus block may improve the success rate due to its radiologic and accurate location of the neurovascular sheath.

CLINICAL AND RADIOLOGICAL COMPARISON OF PERIVASCULAR AND TRANSARTERIAL TECHNIQUES OF AXILLARY BRACHIAL PLEXUS BLOCK

The perivascular technique of axillary brachial plexus block results in incomplete block of radial and musculocutaneous nerves in 10-20% of patients. With the transarterial technique and a large dose of mepivacaine, success rates of 99% have been reported. We have compared the clinical efficacy of these techniques in 50 patients using 1% mepivacaine 45 ml with adrenaline. If required, the block was supplemented with additional blocks of single nerves or i.v. alfentanil. Additionally, eight patients in each group were studied with computed tomography after contrast medium was added to 0.5% bupivacaine 40 ml. There were no statistically significant differences in sensory or motor block between the groups at 20 min or in the plasma concentrations of mepivacaine measured 0-45 min after injection. In the CT scans, both proximal and distal spread of the contrast medium were more common after perivascular than after transarterial block. The distribution of the contrast medium was not related to the efficacy of the block.

Should supraclavicular brachial plexus block be avoided in pregnancy?

Unilateral phrenic nerve block is common after supraclavicular brachial plexus block techniques, although it is rarely symptomatic in patients without respiratory disease. A 24-weeks-pregnant woman was scheduled for a carpal tunnel release because of intractable pain. After a perivascular subclavian brachial plexus block with 30 ml of 0.33% plain bupivacaine was performed, the patient developed a right phrenic nerve block manifested by acute dyspnea and cough. No deleterious consequences followed, but surgery was canceled. Respiratory changes produced by pregnancy might compromise ventilatory reserve. Thus, we suggest avoiding supraclavicular approaches to brachial plexus block in pregnant women, since they may be as prone to developing respiratory embarrassment, secondary to phrenic block, as patients with pulmonary pathology.

Comparison of the clinical efficacy of three techniques of axillary brachial plexus block

Comparison of the clinical efficacy of three techniques of axillary brachial plexus block

COMPARISON OF TWO METHODS OF AXILLARY BRACHIAL PLEXUS ANAESTHESIA

Comparison of the trans-arterial and Winnie techniques of axillary brachial plexus block was made in two groups of patients. This study did not find any statistical difference between the two techniques.

Functional anatomy of the brachial plexus sheaths.

The brachial plexus sheath was examined in cadavers by using a combination of anatomic dissection, histologic preparations, and x-rays made after injection of x-ray contrast media, and in surgical patients by using computed tomography (CT) dye studies. The connective tissue forming the sheath was organized more densely proximally near its origin and became loosely organized distally as it ended by joining the medial intermuscular septum of the arm. The connective tissue forming the sheath extends inward, forming septa between components of the plexus. Thus, the sheath is a multicompartmented structure, formed by the thin connective tissue sheath surrounding the plexus and by the septa which extend inward from the sheath. A fascial compartment is created for each nerve, and this compartment serves to define the anatomic limits of that nerve. These compartments have potential clinical importance and implication in the techniques for brachial plexus block. They serve functionally to limit the circumferential spread of injected solutions of local anesthetics. These studies also indicate that injected anesthetic solutions spread easily in a longitudinal manner up and down the nerve and remain compartmentalized. The data presented here provide a rational explanation for the not uncommon occurrence of a profound block of rapid onset in one nerve, yet partial or absent block in other nerves, following any of the techniques of brachial plexus anesthesia.

The Extent of Blockade Following Various Techniques of Brachial Plexus Block

The Extent of Blockade Following Various Techniques of Brachial Plexus Block

Technique du bloc plexique prolongé par voie axillaire

A technique of continuous axillary brachial plexus block, using an epidural Tuohy needle and an epidural catheter, is described. Studies were carried out in ten patients using this technique with bupivacaine as a local anesthetic drug. The catheter remained indwelling during a mean period of five days. Good analgesia was obtained in nine out of the ten patients. Thus this technique allows pain-free postoperative period in hand surgery.

Factors Influencing Distribution of Local Anesthetic Injected into the Brachial Plexus Sheath

Several technical modifications of the various perivascular techniques of brachial plexus block have been advocated but their efficacy has never been documented. The present study used injections of radiopaque anesthetic solutions to illustrate the effect of various technical maneuvers on the flow of the solutions injected into the sheath at several levels. Axillary block studies indicated that solutions injected through a needle placed high in the axilla and centrally directed achieve a higher level than similar volumes injected through a needle that is perpendicular to the neurovascular bundle at the more traditional lower level. Furthermore, the studies demonstrate that a rubber tourniquet applied around the arm distal to the needle is unable to prevent retrograde flow of the injected solution, especially when the usual volumes utilized clinically are injected. Firm digital pressure applied immediately distal to the needle, on the other hand, is effective in preventing retrograde flow and, in so doing, enhances central flow. Bringing the arm to the side while maintaining digital pressure results in even further central spread by removing the obstacle provided by the head of the abducted humerus. Studies carried out using the infraclavicular technique indicate that because the direction of the properly placed needle is lateral, most of the injected solution passes distally out along the sheath. Again, firm digital pressure high in the axilla occludes the sheath, preventing distal flow and causing the solution to move centrally. Studies carried out using the interscalene technique show that with the usual technique the injected solution moves cephalad into the cervical portion of the sheath as well as caudad into the brachial portion. Firm digital pressure applied superior to the needle prevents cephalad flow and thus forces all of the injected solution to move caudally as far as the dome of the lung and laterally into the axillary sheath.

Brachial plexus block. A double-needle technique via the axillary route.

A new double-needle technique for brachial plexus block via the axillary route has been used in 30 patients. The results have been evaluated against those of a control group in which the classic method for the block was used. Simplicity in performance, high success rate, and a reduced chance of traumatizing the neurovascular tissue stand out as advantages of the new technique.

A Safe Technique for the Supraclavicular Brachial Plexus Block

<h3>To the Editor:</h3> —A safe and simple technique for the supraclavicular brachial plexus block is to locate the plexus by palpation. The head must be turned to stretch the nerves, and the shoulder must be depressed so the clavicle will not cover the brachial plexus as it crosses the first rib. The palpating finger is placed in the angle formed by the clavicle and external jugular vein. The first rib, subclavian artery, and the insertions of the anterior scalenus and clavicular head of the sternocleidomastoid muscles are identified. Firm pressure is exerted in the region of insertion of the anterior scalenus, and the finger is moved along the rib until the nerves are crossed; the nerves are identified by their denser structure, tenderness, and, sometimes, paresthesia to the arm. The plexus is then held impinged between the finger and the rib until the block needle is inserted directly into the